The invention relates to secondary parts for linear motors, in particular synchronous linear motors.
Such linear motors include a primary part in which several coils are placed in linear arrangement, and a secondary part, in which several permanent magnets are placed in linear arrangement in accordance with the pole pitch measure of the primary part. The primary part is fed with electric energy and interacts with the secondary part via an air gap.
In operation, a portion of the electric energy in the primary part is converted into heat, and it is known to cool the primary part via cooling coils, whereby the cooling coils are normally attached on the coils-distal side of the primary part.
The secondary parts normally include a metallic carrier plate on which the permanent magnets are arranged, wherein the permanent magnets can be embedded in a casting compound (DE-A-19936064).
In operation, the secondary parts also heat up, whether as a result of electromagnetic interaction with the primary part, or whether as a result of heat radiation from the primary part onto the secondary part.
Although, it is possible to attach also a cooling pipe upon the metal plate of the secondary part; this, however, requires complicated assembly steps for securing the cooling pipe and possibly drilling and/or milling operations on the carrier plate.
It is therefore the object of the invention to provide a secondary part or a secondary part element for a linear motor, which can be provided in a simple manner with a cooling device.
This object can be attained by a secondary part element for a linear motor with a carrier plate for support of several permanent magnets, wherein the permanent magnets are embedded in a cast body upon the carrier plate, wherein the cast body has longitudinal grooves for receiving cooling pipes. According to another aspect of the invention, a secondary part includes several juxtaposed secondary part elements wherein the grooves are arranged in aligned relationship, and single-piece cooling pipes are received in the aligned grooves.
According to the invention, it is proposed to provide longitudinal grooves in the cast body of the secondary part for receiving the cooling pipes. These longitudinal grooves can be realized in a simple manner during casting of the secondary part, without requiring further finishing works upon the carrier plate of the secondary part.
The grooves extend hereby preferably at a depth up to the surface of the carrier plate in order to establish at least a mechanical contact between cooling pipes, which are placed into the grooves, and the surface of the carrier plate.
Preferably, the grooves have a cross section which corresponds at least partially to the cross section of the cooling pipes, and the grooves have undercuts so that the undercuts form locking means for the cooling pipes. In this case, the cooling pipes are only required to be xe2x80x9cclaspedxe2x80x9d into the grooves, i.e. they snap into the grooves, without requiring additional fasteners.
The arrangement according to the invention is especially suitable for secondary parts which are composed of several secondary part elements. In this case, the grooves are arranged in aligned relationship, and single-piece cooling pipes can be placed in all grooves of the juxtaposed segments.